Synthesis and Charactisation Hydrophobicall Modified Polyacrylamides
Shu Hui, Robert A.
RMIT
Austrlia

Keywords: Hydrophobically, Modifed, Polyacrylamide


Hydrophilic polyacrylamide (PAM) has been hydrophobically modified by N-alkylation with low amounts of alkyl groups using grafting methods. Using alkyl amines, the amide group in the polymer backbone has been N-substituted in water solutions. The alkyl groups include n-alkyl (up to n-octyl), diethyl, dipropyl, isopropyl, diisopropyl, and cyclohexyl groups. This grafting method is convenient compared with traditional micellar copolymerisation methods. However, a limitation of the method is due to failure of substitution of the highly hydrophobic groups such as dodecyl. The mutually incompatible solubility of the starting materials makes it difficult for the reaction to take place in water. Other solvents were tried, including dimethylsulfoxide and ethylene glycol, without significant improvement in level of substitution. Other alkyl substitution methods using haloalkane where performed using the strongly basic catalyst, potassium t-butoxide. The product, N-alky PAM were characterised using infrared and nuclear magnetic resonance (NMR) spectrocopy. Infrared spectra showed an addition of secondary amide absorption after reaction. NMR showed the amount of substitution and changes in the chemical shifts in 1H and 13C NMR after substitution in relation to the structure of the N-alkyl substitutents.